This is a huge improvement, it would be great to roll this out to the OSM homepage.

One of the other frustrating shortcomings of the current history features on the web site, which your panel goes some way to fixing, is that you can't visualise features that have been deleted. A next step would be to show the feature in the map view on pages like http://www.openstreetmap.org/browse/way/131004269

@Tom: Exactly. One of the major features of OWL (the service that powers this new History tab) is that it tracks changes in geometry so it's possible to even show some nice animation on node/way/relation history page to show how given object has changed during its life.

Often with these monitoring tools, I see that somebody has made some changes but when I look at the changeset I can't really work out what they have done. Have they shifted a road 10m to the east, or just touched some nodes while making other changes in the area? Is this changeset something I should check or ignore? It's almost impossible to tell at the moment.

Yeah, that's the challenge I'm trying to tackle with OWL and the new History tab. The technical problem is that it's not easy to track changes - all database schemas and, in general, data sources that we have are geared towards rendering and/or having only current data. That's not enough when you want to analyze changes - which by definition requires you to have the "before" state and the "after" state to calculate what's changed.

If you have any suggestions on how to improve the usefulness of this tool then please don't hesitate to create new issues on Github:

Oh thank GOODNESS you're doing this :) the history tab is so unhelpful because filled with worldwide edits that usually don't even have any content in the current bounding box. Looking forward to this.